For best traction, tires should have adequate tread and be properly inflated. Overinflating a tire causes excess wear in the centre part of its tread. An overinflated tire has less tread surface in contact with the road surface. Less contact between your tire and the road means less traction. Underinflating a tire causes excess wear on the outer edges of its tread. Under wet conditions, an underinflated tire will not channel the water away very well, which may lead to hydroplaning.